As for a conventional solenoid valve, for example, those having a part of shaft having a hollow pipe shape being fixed by introducing into a through hole formed at the plunger, and a part of the shaft moves inside the magnetic opposing portion which magnetically attracts the plunger, is proposed (refer to Patent document 1).
Also, in the conventional arts, in order to prevent the plunger and the magnetic opposing part from being connected, the technique to place the plate in between the shaft and the plunger, the technique to process the end face of the plunger, or the technique to bend a part of the shaft are proposed.